I think you mean polyps.
You can get polyp, cyst and nodule growths on vocal chords, but I do not know how long they would take to form. Obviously if you abuse your voice a lot and expose it to pollutants, it would be sooner than later.
Having thick mucus in your throat can also go down and coat the vocal chords. A good way to help loosen the mucus and allow it to drain or spit it out, is by doing steam inhalations. Do this 4 times a day for 10 minutes each time, but take care not to get scalded. To do a steam inhalation, pour very hot water into a bowl, add Vick or Olbas Oil if you wish, bend over the steamy bowl and cover your head and bowl with a towel and inhale the steam.
If you have a problem with the voice, it could be due to the mucus which may be a viral or bacterial infection or caused through allergies to smoke and dust.
Exposing the vocal chords to pollutants (that includes smoking and being in a smoky environment) can cause problems with the larynx (voice box).
Shouting and talking very loudly or talking or singing a lot and straining the voice can also damage the vocal chords. When singing, it is always important to do vocal warm up exercises to loosen up the chords so that you do not strain the vocal chords when singing.
If you suffer from gastric problems like acid reflux, or GERD, that too can damage the vocal chords as the gastric fluids enter the oesophagus.
If you are having a voice problem and have not had your throat examined, it would be a good idea to see a doctor to examine your throat and also check if you do suffer from acid reflux. There are medications to dry up the mucus, but these are not suitable for everyone. Nasal sprays are also sometimes prescribed to decongest the passages. You can't go wrong with inhalations as long as you take care not to get scalded.
Make sure that you also drink plenty of water and fluids and rest your voice.
Whispering can be just as damaging to the vocal chords as shouting.
Unfortunately, if you do have any growths on the vocal chords, these will not heal and repair on their own and you may require surgery to remove them if you rely on your voice in your work.